1. The Field of the Invention
The present invention broadly relates to novel liquid oxyalkylated polyol prepolymers and processes for the preparation thereof. The invention also relates to novel solid or cellular interpolymers prepared from the oxyalkylated polyol prepolymers, and processes are further provided for preparing the solid or cellular interpolymers. In some of the specific variants, the invention is concerned with novel closed cell cellular interpolymers and solid or cellular polyurethanes prepared from the oxyalkylated polyol prepolymers.
2. The Prior Art
Polyol prepolymers have been prepared heretofore by interpolymerizing certain hydroxy aromatic compounds, aldehydes and furfuryl alcohol. The resultant non-oxyalkylated polyol prepolymers are known to be reactive and capable of being further polymerized. However, the prior art non-oxyalkylated polyol prepolymers usually contain less than 3.0 moles of interpolymerized furfuryl alcohol for each mole of the interpolymerized hydroxy aromatic compound and/or upon further polymerization, the interpolymers prepared therefrom do not consistently have good mechanical and/or physical properties in combination with a high degree of flame retardance. It was also impossible to prepare foams therefrom having predominately closed cells.
The above prior art non-oxyalkylated polyol prepolymers also tend to have widely varying properties from run to run, and especially with respect to the viscosity, molecular weight and ratio of interpolymerized monomers. Upon oxyalkylation and further polymerization of the prior art polyol prepolymers, it was not possible heretofore to prepare solid or cellular interpolymers having predictable and reproducible mechanical and/or physical properties. This is especially true when preparing in place low density cellular interpolymers having densities of approximately 1-10 pounds per cubic foot of the type often used for thermal and/or sound insulation. The flame retardant properties of these solid or cellular prior art interpolymers also are not outstanding when used in environments where a fire hazard exists such as in certain construction and industrial applications.
As a result of the aforementioned and other disadvantages and/or deficiencies, the art has long sought without success an entirely satisfactory process for preparing novel liquid prepolymers of the above defined type which have reproducible molecular weights, viscosities and interpolymerized monomer contents, a process for the oxyalkylation thereof to produce novel oxyalkylated polyol prepolymers which likewise have these properties, and also a process whereby the resultant prepolymers may be further polymerized with or without other monomers to produce improved interpolymers characterized by excellent mechanical and/or physical properties in combination with exceptional flame retardant properties. The prior art also has long sought a process for preparing closed cell foam from the prepolymers. However, such processes and the novel prepolymer and interpolymer products prepared thereby were not available prior to the present invention.